In general, in the field of semiconductor technology, the performance of a component is strongly dependent, inter alia, on the permissible operating temperatures. A very common reason for component failure is temperatures which are too high during operation, which damage or even completely destroy the component. Both for the user who dimensions a specific application, and for the semiconductor manufacturer that specifies its product, the knowledge of the component temperature that result under specific field conditions is therefore of great interest.
Thus, the problem of detecting the component temperature, particularly transient changes of temperature in the interior of the component during operation, is important.
At the moment, the following approach to solving this problem is found in the prior art. The so-called barrier-layer temperature or junction temperature Tj is determined via the measurement of the forward voltage of p-n junctions of the component. The p-n junctions are junctions between p-doped and n-doped regions of a semiconductor, and they are, for example, a component of rectifier and Zener diodes, or exist in the form of the intrinsic body diode of a field-effect transistor or MOSFET transistor.
This known approach utilizes the fact that the voltage, which must be applied in the forward direction to a p-n junction for a specific current flow, is a function of the component temperature at the location of the p-n junction. Based on the functional correlation of the voltage, of the current and the component temperature, by measuring the forward voltage with respect to a given forward current, it is possible to infer the component temperature.
In the known approach above, the fact that the measurement current must flow in the forward direction across the component turns out to be disadvantageous, i.e., this method is not usable as long as another operating state of the component prevents this forward current. Even during such operating states, however, it is often necessary to exactly determine the internal temperature conditions of the component.
For example, using this known method, it is not possible to examine the reverse breakdown of a diode, in which a high voltage is applied in the reverse direction, such that the diode breaks down and a high so-called avalanche current flows in the reverse direction. The high fields and currents lead to strong heating of the component, the hottest location in the component being precisely at the p-n junction which is breaking down. However, to determine the temperature prevailing at the p-n junction using the approach described above, it is necessary to wait until the reverse current has nearly completely decayed, in order to be able to allow a measurement current to flow in the forward direction through the component. This time delay results in an inaccurate measurement, since the temperature now present no longer corresponds to the temperature peak at the p-n junction occurring during the breakdown, because in the meantime, the heat has already been distributed over a larger area of the component or to the thermally coupled surroundings of the component.
However, it is precisely the transient temperature peaks which are critical in damaging the component and which cannot be measured sufficiently accurately using the above approach according to the prior art.